Vampires are nocturnal, mythical creatures who have become a favorite of millions of teenagers due to the popular movies and fictions. They have always evoked curiosity and an aura of mystery. There are many stories and folk lore regarding the vampires but though the details change from one region to another one fact remains the same. The vampires survive on human blood. They are also called blood-suckers. Now the question which we all want answered is why do vampires drink blood? There are so many opposing theories at work regarding the blood lust of vampires that anyone can become confused.